extrusion of a flat sketch from a cylindrical surface

[EmmePrevi]

I am sorry if this problem may be trivial or badly exposed; I will do my best.

I have a hollow cylinder (which I will call 1) and from its surface I should go to extrude a circle to create a second smaller cylinder (which I will call 2). to create the cylinder sketch 2 I use the function "parallel plane", which allows me to have a tangent plane to the cylinder surface 1. the problem arises obvious at the time of extrusion : it advances space between cylinder 1 and cylinder 2 (treating parts "nate" from a 2d sketch and a 3d cylindrical body).

an alternative I found it with the winding function; I was able to "transport" the 2d circle sketch on the cylindrical surface, but it didn't allow me to extrude.

I hope I made myself understand, in case I can post pictures. Thank you in advance :smile:

 

[MassiVonWeizen]

Obviously posting pictures or files would be better.
said this make an extrusion with two directions; one blind and the other up to the body, or do medium-sleeping and then cut the excess using the cable cylinder.

do the internal tutorials to the program

 

[MassiVonWeizen]

I add other methods:
- use the structural members and then, if it has not done so of its own, use the commotion/extension.
- make the plane coincide with the end of cylinder 2 and then extrude to the body or surface